1. Field of the Invention
The present invention refers to a device for positioning the blade edge of a cutting machine and intermittently lowering the blade cutting edge. More particularly this invention refers to a device for positioning and intermittently lowering the blade "edge" for the continuous cutting of films, or very thin films suitable for the packing of various products.
2. Description of the Prior Art
Different devices are known, that may be termed "blade carriers", which, in a mobile manner, support a thin cutting "blade" designed to cut film-like material, to obtain strips to be used generally in the packing of various products.
To achieve the alternate movements of the blade fitted on a "blade-carrier" the known devices use a series of cams that mechanically impart the desired movement to the blade-carrier in order to sequentially move the position of the blade during the cutting operation.
Other devices are also known which are not fitted with alternate mechanical controls, but that require periodic displacement of the blade along the blade-carrier, to change the position in which the "edge" cuts the film.
All these known devices have different drawbacks and limitations. In fact, the devices where the alternating movements of the blade-carrier are achieved mechanically, include a shaft to operate the numerous cams.
Generally, the shaft requires complex and costly processing and may have a considerable longitudinal size to be used in the various types of blade carrier to be operated.
Therefore, the said devices are mechanically complicated and difficult to position and calibrate.
Whereas, on the other hand, in the case of blade-carrier devices in which recourse is made to the repeated displacement of the blade in the blade-carrier, there are consequently frequent interruptions in the film cutting operations. In addition, in the known devices a straight cut by the blade is not assured, since the movements of the blade-carrier are not rationally guided.